Vessel, dispensing devices, kits and methods for containing fluids

STATEMENT WITH RESPECT TO FEDERAL SPONSORSHIP

The present invention was made without Federal sponsorship or funds.

FIELD OF THE INVENTION

Embodiments of the present invention are directed to devices for transferring and holding fluids under atmosphere while minimizing fluid loss through evaporation.

BACKGROUND OF THE INVENTION

The following terms, defined below, will be used to describe embodiments of the present invention.

Chromatography is the science of separating compounds held in solution. The compounds are separated by flowing the solution through a stationary phase. Compounds held in the solution exhibit different affinity for the stationary phase and separate from each other. Common stationary phases are solids such as a packed bed of particles, beads, fibers, and structures known in the art as “porous monoliths”. These solid stationary phases will be referred to herein as solid phase separation media, or simply, separation media.

Solid phase extraction devices are devices that use a solid stationary phase to perform a chromatographic separation. Common solid phase extraction devices include columns, cartridges and funnel-like devices which have one or more chambers containing a separation media. Particularly in the study of biological processes, it is desirable to work with small volumes. If the sample is obtained from a living organism, such small sample may not be as disruptive as a larger sample. Many biological samples can only be obtained in a small volume.

However, as fluid sample size decreases, the sample becomes increasing difficult to handle without losses. These losses may come from fluid retained on transferring devices such as solid phase extraction devices, pipettes, vials, conduits and cuvettes or evaporation. As used herein, the term “evaporation” refers to the change in phase of a liquid to a gas.

SUMMARY OF THE INVENTION

Embodiments of the present invention are directed to devices, kits and methods for performing fluid transfer operations and chromatography that limit loss of sample through evaporation.

One embodiment of the present invention is directed to a device for limiting sample evaporation. The device has a vessel body having a body exterior surface and at least one body interior surface. The at least one body interior surface has one or more walls defining a first chamber, a second chamber and a conduit means. The first chamber has a first chamber opening for receiving at least one of the group selected from a sample and a sample dispensing device. The first chamber opening defines the border of the body exterior surface and the body interior surface. The conduit means is in communication with the first chamber and the second chamber for receiving at least one of the group consisting of sample from said first chamber, a sample from a sample dispensing device and a sample dispensing device passing through or into the conduit means for placing the sample in the conduit means or into the second chamber. The second chamber is in communication with the conduit means for receiving and containing the sample from at least one of the group selected from the sample dispensing device and conduit means. The conduit means is arranged such that the sample in the second chamber is substantially isolated from the atmosphere to limit sample evaporation in the second chamber as the sample is contained therein.

As used herein the term “conduit means” is used to denote a tube, passageway, membrane or any other device that can substantially separate the first and second chamber in such a way to limit the flow of air from the atmosphere into the second chamber but not to prevent sample access to the second chamber, or extraction from the second chamber for further analysis

For example, one conduit means has at least one conduit cross sectional area and the second chamber has a cross sectional area wherein the conduit means cross sectional area is less than the cross sectional area of the second chamber to limit the exchange of atmosphere between the second chamber and the first chamber. The “cross sectional area of the conduit means” refers to the area of a plane perpendicular to the flow of fluid through the conduit means. The “cross sectional area of the second chamber” refers to at least one volume of fluid in which the volume is associated with a fluid level in the second chamber and the plane defined by such level in the second chamber is at its widest point. A preferred second chamber is spherical, presenting a maximum area for a wetted surface.

And, as a further example, wherein the conduit means features a membrane, one embodiment features a membrane having a membrane opening. The membrane opening has a conduit cross sectional area. The second chamber is constructed and arranged to receive a fluid sample having at least one volume in which the at least one volume has a fluid level in the chamber and the fluid level in the second chamber defines a second chamber cross sectional area. The conduit means cross sectional area is equal to, and, more preferably, less than the cross sectional area of the second chamber to limit the exchange of atmosphere between the second chamber and said first chamber.

Further examples of preferred membranes are a permeable membrane, a membrane having a slit, membrane having opening formed by the force of the fluid, for example, upon centrifugation, or a membrane that forms an opening upon being pierced by a dispensing device.

Preferably, the vessel body is adapted and constructed to be received in a centrifuge to propel fluid to move from the first chamber through the conduit means and into the second chamber. The second chamber, substantially isolated from the atmosphere by the conduit means, limits evaporation and maintains the integrity of the sample.

A preferred embodiment of the device is constructed and arranged to receive sample from a sample dispenser. As used herein the term “sample dispenser” refers to a autosampler, pipette, needle, syringe, tip or other separate device for funnelling fluid samples. A preferred sample dispenser is an autosampler. Autosamplers are well known in the art and commonly employ a needle to withdraw or inject fluid samples.

Preferably, the first chamber opening and said first chamber receive a sample dispenser.

A preferred sample dispenser has a dispenser housing having a housing exterior surface, at least one housing interior surface, a first end and a second end. The interior surface and exterior surface define at least one housing inlet at the first end and at least one housing outlet at the second end. The interior wall between said housing inlet and the housing outlet defines a passage for conveying and holding sample for dispensing from the housing outlet.

Preferably, with automated systems, such as autosamplers, one embodiment of the present invention features conduit means and the first chamber receiving the dispenser housing with the housing outlet projecting into said second chamber.

Preferably, with tips and other small portable dispensing means, at least one of the sample dispenser and the vessel body have retaining surfaces to hold the sample dispenser and vessel body in position to place fluid sample into at least one of said first chamber, second chamber and conduit means.

A preferred retaining surface comprises a rim at the first chamber opening and at least one abutment ridge projecting outwardly from the dispenser housing which, in cooperation with the rim hold the sample dispenser in position.

A preferred sample dispenser is capable of performing chromatographic separations. One embodiment of the invention features a sample dispenser having a passage with at least one media section. The media section may be a solid phase extraction media through which fluid samples flow to effect a separation.

A preferred media section has a frusto-conical shape in which said media section towards said first end, the housing inlet, has a larger cross sectional area than said media section towards said second end, the housing outlet. Preferably, the media section has at least one frit element to retain the solid phase separation media. A preferred frit element is a porous sphere.

The sample dispenser with separation media can effect a chromatographic separation upon sample flowing through the passage from said housing inlet to the outlet. However, those skilled in the art will recognise that the sample dispenser can be used in the manner of a pipette tip to withdraw a fluid sample through the housing outlet by applying a vacuum to the housing inlet to effect a separation in the opposite direction.

Preferably, at least one of the dispenser or vessel body is adapted and constructed to be received in a centrifuge. One embodiment of the present invention features a dispenser housing and vessel body constructed to be received in a centrifuge. The dispenser housing receives a fluid sample and directs the fluid sample into the first chamber, conduit means or second chamber upon application of centrifugal force.

Preferably, the vessel body has at least one third chamber in fluid communication with or capable of being placed in fluid communication with said first chamber. The third chamber is arranged such that fluid in the third chamber will increase the level of saturation of the atmosphere in the first chamber, and hence to reduce the evaporation of the sample in the second chamber. A preferred third chamber surrounds said first chamber.

A further embodiment of the present invention features a vessel body and a plug element. The plug element is constructed and arranged to be received in the first chamber or the conduit means to close the second chamber from the atmosphere.

Embodiments of the present invention are also directed to a device for performing separations for use with a vessel having a vessel body. The vessel body has been described previously as having a body exterior surface and at least one body interior surface. The body interior surface has one or more walls defining one or more chambers and at least one of the one or more chambers has an opening. The dispenser has a dispenser housing having a housing exterior surface, at least one housing interior surface, a first end and a second end. At least one interior surface and exterior surface define at least one housing inlet at the first end and at least one housing outlet at the second end. The housing inlet, the housing outlet and the one interior wall define a passage for holding and/or conveying fluid sample for dispensing from said housing outlet. At least one of the sample dispenser and the vessel body have retaining surfaces to hold the sample dispenser and vessel body in position to place a fluid sample into at least one of the chambers of the vessel body and the dispenser housing and vessel body are subjected to centrifugal force.

Preferably, the retaining surfaces comprise a rim at the chamber opening and at least one abutment ridge projecting outwardly from the dispenser housing.

Preferably, the passage has at least one media section comprising a solid phase extraction media. A preferred media section has a frusto-conical shape in which said media section is towards said first end and has a larger cross sectional area than said media section towards said second end. And, preferably, the media section has at least one frit element. A preferred frit is a porous sphere.

A further embodiment of the present invention is directed to a kit for performing fluid transfers. The kit comprises a vessel body and a dispenser housing as previously described. As used herein, the term “kit” refers to an assembly of parts packaged or bundled for a common purpose. Such kits may include instructions for the use of the item and other parts and supporting equipment.

Preferably, at least one of the dispenser housing and the vessel body is adapted and constructed to be received in a centrifuge.

Preferably, the kit comprises a plug element for sealing the second chamber from said first chamber.

Preferably, the vessel body, dispenser housing and plug element, if so equipped, has indicia to link each with each other. Such indicia has value for quality control, to ensure fluid samples from one dispenser housing, or plug element, intended for one vessel body do not end up in the wrong vessel body.

Preferably, one or more elements of the kit are linked by tethers, for example, without limitation, monofilament lines. For example, without limitation, one embodiment of the present invention features a tether between the plug element and the vessel body. In the event the tether is not desired, the tether can be readily clipped.

A further embodiment of the present invention is directed to a method of transferring and/or containing a fluid sample under conditions which limit evaporation. The method comprises the step of providing a vessel body having a body exterior surface and at least one body interior surface. At least one body interior surface has one or more walls defining a first chamber, a second chamber and a conduit means. The first chamber has a first chamber opening for receiving at least one of the group selected from a sample and a sample dispensing device. The first chamber opening defines the border of the body exterior surface and the body interior surface. The conduit means is in communication with the first chamber and the second chamber for receiving at least one of the group consisting of sample from the first chamber, a sample from a sample dispensing device and a sample dispensing device passing through or into the conduit means for placing the sample in the conduit means or into the second chamber. And, the second chamber is in communication with the conduit means for receiving and containing the sample from at least one of the group selected from said sample dispensing device and conduit means. The conduit means is arranged such that said sample in said second chamber is substantially isolated from the atmosphere to limit sample evaporation in the second chamber as the sample is contained therein. The method further comprising the step of placing a fluid sample in at least one of said first chamber, conduit means and second chamber.

Preferably, the method comprises the step of centrifuging the vessel body to move fluid into the second chamber.

Thus, embodiments of the present invention are directed to devices, apparatus, kits and methods providing sample evaporation limiting devices with a conduit means arranged to substantially isolate samples from the atmosphere. These and other benefits will be apparent to those individuals skilled in the arts upon viewing the drawings and reading the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idrefs="DRAWINGS">FIG. 1</figref> depicts an apparatus in accordance with the invention

<figref idrefs="DRAWINGS">FIG. 2</figref> depicts an alternative embodiment of the invention

<figref idrefs="DRAWINGS">FIG. 3</figref> depicts an embodiment of the invention with a sample dispensing device

<figref idrefs="DRAWINGS">FIG. 4</figref> depicts a further embodiment of the invention

<figref idrefs="DRAWINGS">FIG. 5</figref> depicts an embodiment of the invention engaged to a dispenser

<figref idrefs="DRAWINGS">FIG. 6</figref> depicts an embodiment of the invention as a kit

<figref idrefs="DRAWINGS">FIG. 7</figref> depicts a graph of weight against time for an apparatus substantially in accordance with the invention and a standard vial container

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described with respect to sample preparation for chemical analysis with the understanding that the invention has broad application in other fields as well.

Turning now to <figref idrefs="DRAWINGS">FIG. 1</figref>, such figure depicts in cross section an apparatus, generally designated by the numeral <b>10</b>, for use with a standard laboratory centrifuge [not shown]. Standard laboratory centrifuges are known in the art and are available from several vendors.

The apparatus comprises a vessel body (<b>12</b>) having a body exterior surface (<b>14</b>) and at least one body interior surface (<b>16</b>). The body interior surface has one or more walls, such as walls (<b>18</b><i>a </i>and <b>18</b><i>b</i>) defining a first chamber (<b>20</b>), walls (<b>18</b><i>c </i>and <b>18</b><i>d</i>) defining a second chamber (<b>22</b>) and walls (<b>18</b><i>e </i>and <b>180</b> defining a conduit means (<b>24</b>).

The first chamber (<b>20</b>) has a first chamber opening (<b>26</b>) for receiving a sample (<b>28</b>). The first chamber opening (<b>26</b>) defines the border of the body exterior surface (<b>14</b>) and the body interior surface (<b>16</b>).

The body (<b>12</b>) is made of fused silica, glass, plastic or metal. Preferred plastics are selected from one or more thermoplastics currently available as exemplified in the text <i>Modern Plastics Handbook</i>, Charles A Harper, editor; McGraw-Hill (2005). Preferred plastics comprise polyethylethelketone, sold under the trademark PEEK™ (Dupont), Polyfluoroalkyl polymers sold under the trademark TEFLON® (Dupont) and PTFE, polyimide polymers, polyamide imide polymers, polyethylene polymers, polyvinylindene fluoride polymers, polychlorofluoroalkyl polymers, known in the trade as PCTFE.

The sample (<b>28</b>) is depicted as having entered the first chamber (<b>20</b>) through the first chamber opening (<b>26</b>), passing the conduit means (<b>24</b>) and resting in the second chamber (<b>22</b>). As used herein, the term “sample” refers to any material which is subject to evaporative processes. By way of example, without limitation, the sample may comprise fluids, liquids, gels, suspensions, solutions, and material of biological origin such as tissues, blood, plasma, urine, cerebral spinal fluid, sputum and others.

Sample (<b>28</b>) may also be placed in device (<b>10</b>) by means of a sample dispensing device [not shown], such as a needle, syringe, pipette, micropipette, dropper and the like, known in the art. The sample dispensing device may be manually operated or part of a larger instrument such as an autosampler [not shown]. Autosamplers are available from several vendors as individual instruments and as integrated components, for example, the ALLIANCE® separations module, sold by Waters Corporation (Milford, Mass., USA) comprises an autosampler with a chromatography system.

The conduit means (<b>24</b>) is in communication with the first chamber (<b>20</b>) and the second chamber (<b>22</b>). The conduit means is for receiving the sample (<b>28</b>) or a sample dispensing device [not shown]. The sample may come from the first chamber (<b>20</b>), or from a sample dispensing device. Or, conduit means (<b>24</b>) receives a sample dispensing device passing through or into the conduit means (<b>24</b>) for placing the sample (<b>28</b>) in the conduit means (<b>24</b>) or into the second chamber (<b>22</b>).

As depicted in <figref idrefs="DRAWINGS">FIG. 1</figref>, conduit means (<b>24</b>) is a membrane (<b>32</b>). Membrane (<b>32</b>) has an opening (<b>34</b>) or features which will create an opening (<b>34</b>). For example, the membrane (<b>32</b>) may be scored to create an opening (<b>34</b>) upon pressure from a fluid during centrifugation. In the alternative, the membrane (<b>32</b>) may cooperate with dispensing means such as a needle to allow piercing. A preferred opening is a slit. Upon addition of sample (<b>28</b>), the membrane (<b>32</b>) deforms under the weight of a droplet of sample that is resting against it, allowing the droplet to fall into the second chamber (<b>22</b>). Once the droplet descends, the slit closes or partially closes.

The membrane (<b>32</b>) is preferably made of a material exhibiting elastic characteristics, such as a material selected from one or more thermoplastics currently available as exemplified in the text <i>Modern Plastics Handbook</i>, Charles A Harper, editor; McGraw-Hill (2005). These materials have been discussed with respect to the body (<b>12</b>).

Those skilled in the art will readily recognise that the membrane (<b>32</b>) can have a plurality of holes or openings [not shown] in a manner known in the art to form a permeable membrane or a breakable membrane. Membranes having features of permeability or capable of breaking or tearing are preferably made of plastics as previously described or foils such as aluminium.

As depicted in <figref idrefs="DRAWINGS">FIG. 1</figref>, the membrane (<b>32</b>) has a membrane opening (<b>34</b>) or such opening is made as previously described by needles or the force of the fluid held in the first chamber (<b>20</b>). The membrane opening (<b>34</b>) has a conduit cross sectional area that is smaller than the cross sectional areas of the first chamber (<b>20</b>) and second chamber (<b>22</b>) adjoining the conduit means (<b>24</b>).

Turning now to <figref idrefs="DRAWINGS">FIG. 2</figref>, a device (<b>10</b>′) is depicted in which similar features as described with respect to device (<b>10</b>) of <figref idrefs="DRAWINGS">FIG. 1</figref> bear identical numbers with a prime designation. The conduit means (<b>24</b>′) is depicted as a single opening. The second chamber (<b>22</b>′) is constructed and arranged to receive a fluid sample (<b>28</b>′) having at least one volume which has a fluid level (<b>30</b>′). The fluid level (<b>30</b>′) in the second chamber (<b>22</b>′) defines a second chamber cross sectional area. The conduit means (<b>24</b>′) cross sectional area is less than or equal to the second chamber cross sectional area to limit the exchange of atmosphere between said second chamber (<b>22</b>′) and said first chamber (<b>20</b>′). Preferably, the conduit means (<b>24</b>′) is 10 to 90 percent of the second chamber cross sectional area at the predetermined volume.

Turning now to <figref idrefs="DRAWINGS">FIGS. 1 and 2</figref>, the second chamber (<b>22</b> and <b>22</b>′) is in communication with the conduit means (<b>24</b> and <b>24</b>′) for receiving and containing the sample (<b>28</b> and <b>28</b>′) descending from or through conduit means (<b>24</b> and <b>24</b>′). Or, as depicted in <figref idrefs="DRAWINGS">FIG. 3</figref>, from a sample dispensing device, generally designated as (<b>100</b>). Sample dispensing device (<b>100</b>) is depicted as a needle (<b>110</b>) in communication with a source of sample [not shown]. Needle (<b>110</b>) can be a part of a manual pipette device or an automated sample dispensing device such as a autosampler [not shown].

Returning now to <figref idrefs="DRAWINGS">FIGS. 1 and 2</figref>, the conduit means (<b>24</b> and <b>24</b>′) is arranged such that the sample (<b>28</b> and <b>28</b>′) in the second chamber (<b>22</b> and <b>22</b>′) is substantially isolated from the atmosphere to limit evaporation of sample (<b>28</b> and <b>28</b>′) in the second chamber (<b>22</b> and <b>22</b>′).

Focusing on <figref idrefs="DRAWINGS">FIG. 2</figref>, device (<b>10</b>′) has a plug element (<b>116</b>) comprising a handle (<b>118</b>) and an end plug (<b>120</b>) to facilitate containment and isolation of a sample (<b>28</b>′). End plug (<b>120</b>) has a tab element (<b>122</b>) that is received in the opening comprising conduit means (<b>24</b>′). The tab element (<b>122</b>) has a snap ridge (<b>124</b>) with is cooperates with the conduit opening (<b>24</b>′) to hold the plug element (<b>116</b>) in place by a snap fit.

The handle (<b>118</b>) has a finger grip section (<b>126</b>) to facilitate handling the plug element (<b>116</b>). The length of the handle (<b>118</b>) can protrude above the first chamber opening (<b>26</b>′) or be recessed within the first chamber (<b>20</b>′) to allow the vessel body (<b>12</b>′) to be stacked. A tether (<b>128</b>) holds the plug element (<b>116</b>) to the vessel body (<b>12</b>′). The plug element (<b>116</b>) is made from one or more materials selected from the group comprising glass, fused silica, plastic and metals. Plastic materials allow the tether (<b>128</b>) to be clipped if the plug element (<b>116</b>) is not desired.

Turning now to <figref idrefs="DRAWINGS">FIGS. 1 and 2</figref>, each vessel body (<b>12</b> and <b>12</b>′) is adapted and constructed to be received in a centrifuge [not shown] to propel fluid to move from the first chamber (<b>20</b> and <b>20</b>′) through the conduit means (<b>24</b> and <b>24</b>′) and into the second chamber (<b>22</b> and <b>22</b>′). Centrifuges typically have circular holes in which vials and cuvettes are received. The exterior surface (<b>14</b> and <b>14</b>′) of each vessel body (<b>12</b> and <b>12</b>′) cooperates with the dimensions of the opening of the centrifuge to allow the device (<b>10</b> and <b>10</b>′) to be received therein.

The exterior surface (<b>14</b> and <b>14</b>′) of devices (<b>10</b> and <b>10</b>′) have one or more retention protrusions (<b>36</b> and <b>36</b>′). As illustrated, the retention protrusion (<b>36</b> and <b>36</b>′) is a ring having a diameter that exceeds the diameter of the opening such that the device (<b>10</b> and <b>10</b>′) rests in the opening by such retention protrusion (<b>36</b> and <b>36</b>′).

Turning now to <figref idrefs="DRAWINGS">FIG. 4</figref>, a device (<b>10</b>″) is depicted in which similar features as described with respect to device (<b>10</b>) of <figref idrefs="DRAWINGS">FIG. 1</figref> bear identical numbers with a double prime designation. The vessel body (<b>12</b>″) has at least one third chamber (<b>40</b>″) in fluid communication with or capable of being placed in fluid communication with the first chamber (<b>20</b>″). As depicted, vessel body (<b>12</b>″) has at least one third chamber opening (<b>42</b>″) for addition of fluid (<b>44</b>″) and for placing the third chamber in communication with the first chamber (<b>20</b>″). As depicted, third chamber (<b>40</b>″) surrounds the first chamber (<b>22</b>″).

The third chamber (<b>40</b>″) is arranged such that fluid (<b>44</b>″) in the third chamber (<b>40</b>″) will increase the level of saturation of the atmosphere in the first chamber (<b>20</b>″), and hence to reduce the evaporation of the sample (<b>28</b>″) in the second chamber (<b>22</b>″). Preferably, the further fluid to be added to the third chamber (<b>40</b>″) is a solvent present in the sample (<b>28</b>″).

Those skilled in the art will recognize that multiple third chambers [not shown] for a plurality of fluids can be incorporated in the device in the manner of the single third chamber (<b>40</b>″).

Turning now to <figref idrefs="DRAWINGS">FIG. 5</figref>, as depicted, vessel body (<b>12</b>′) is engaged with a dispenser (<b>50</b>). Dispenser (<b>50</b>) has a dispenser housing (<b>52</b>) having a housing exterior surface (<b>54</b>), at least one housing interior surface (<b>56</b>), a first end (<b>58</b>) and a second end (<b>60</b>). The dispenser is made of materials described with respect to the vessel body (<b>12</b>).

The interior surface (<b>56</b>) and exterior surface (<b>54</b>) define a housing inlet (<b>62</b>) and a housing outlet (<b>64</b>). The housing inlet (<b>62</b>) is at the first end (<b>58</b>) and the housing outlet (<b>64</b>) is at the second end (<b>60</b>). The interior surface (<b>56</b>) between the housing inlet (<b>62</b>) and the housing outlet (<b>64</b>) defines a passage (<b>66</b>) for holding sample. The sample is discharged from the housing outlet (<b>64</b>).

The sample dispenser (<b>50</b>) and the vessel body (<b>12</b>′) have retaining surfaces to hold the sample dispenser (<b>50</b>) and vessel body (<b>12</b>′) in position to place sample into at least one of the first chamber (<b>20</b>′), second chamber (<b>22</b>′) and conduit means (<b>24</b>′). As depicted, the first chamber (<b>20</b>′) receives the dispenser housing (<b>52</b>) with the at least one housing outlet (<b>64</b>) projecting into the first chamber (<b>20</b>′). Sample may be discharged from the housing outlet into the conduit means (<b>24</b>′) or the second chamber (<b>22</b>′) by providing a longer sample dispenser <b>50</b> at the housing outlet <b>64</b>.

The retaining surfaces, as depicted, comprise the rim (<b>126</b>) at the first chamber opening (<b>26</b>′) and at least one abutment ridge (<b>131</b>) projecting outwardly from the dispenser housing (<b>52</b>). Those skilled in the art will recognize that the cooperating retaining surfaces can be reversed, that is, the first chamber (<b>20</b>′) would have on or more inwardly projecting ridges [not shown] which support the dispenser (<b>50</b>) on the housing exterior surface (<b>54</b>). The dispenser housing (<b>50</b>) and the vessel body (<b>12</b>′).

Preferably the passage (<b>66</b>) has at least one media section (<b>70</b>) comprising a solid phase extraction media. Solid phase extraction can be used to purify samples prior to analysis, i.e., to isolate a desired target substance from an interfering substance in a sample medium. An advantage of using the present invention is that it allows the use of smaller elution volume solid phase extraction devices. Solid phase extraction media comprise packed beds of particles, beads, or fibers or monolithic porous materials. These materials are formed of organic and inorganic compositions well known in the art.

The media section (<b>70</b>) has a frusto-conical shape in which the media section (<b>70</b>) towards said first end (<b>58</b>) and has a larger cross sectional area than said media section towards said second end (<b>60</b>). The frusto-conical shape facilitates use of a first porous sphere (<b>72</b>) and a second porous sphere (<b>74</b>) as a bottom frit element and a top frit element, respectively, to retain the media in the media section (<b>70</b>). However, those skilled in the art will recognize that other frit elements such as screens and porous foils and membranes can be readily substituted for the porous spheres (<b>72</b>) and (<b>74</b>).

The dispenser (<b>50</b>) and vessel body (<b>12</b>′) are constructed and arranged to be received in a centrifuge as an combined assembly (<b>150</b>). The relative centrifugal force placed on an individual vessel body (<b>12</b>, <b>12</b>′, <b>12</b>″) or dispenser (<b>50</b>) or combined assembly (<b>150</b>) can be calculated using the formula

<maths id="MATH-US-00001" num="00001"><math overflow="scroll"><mrow><mrow><mi>R</mi><mo>⁢</mo><mstyle><mspace width="0.3em" height="0.3ex" /></mstyle><mo>⁢</mo><mi>C</mi><mo>⁢</mo><mstyle><mspace width="0.3em" height="0.3ex" /></mstyle><mo>⁢</mo><mi>F</mi></mrow><mo>=</mo><mrow><mn>1.12</mn><mo>⁢</mo><msup><mrow><mi>γ</mi><mo>⁡</mo><mrow><mo>(</mo><mfrac><mrow><mi>R</mi><mo>⁢</mo><mstyle><mspace width="0.3em" height="0.3ex" /></mstyle><mo>⁢</mo><mi>P</mi><mo>⁢</mo><mstyle><mspace width="0.3em" height="0.3ex" /></mstyle><mo>⁢</mo><mi>M</mi></mrow><mn>1000</mn></mfrac><mo>)</mo></mrow></mrow><mn>2</mn></msup></mrow></mrow></math></maths>

Where r is the radius of rotation of the sample in mm, and RPM is the number of revolutions that the centrifuge arm will make in 1 minute. It is normally expressed as a multiple of g (gravity in metres per second)

The ideal relative centrifugal force for any sample is dependent upon the viscosity of the sample; The more viscous the sample, the higher the ideal relative centrifugal force. Centrifugation is particularly desirable as the force for powering the sample through a dispenser (<b>50</b>) and/or a vessel body (<b>12</b>, <b>12</b>′ or <b>12</b>″). Centrifugal force does not induce evaporation of the sample like in vacuum extraction, thus allowing smaller quantities of sample to be used.

Preferably the centrifuge applies a relative centrifugal force of between 200×g m/s²and about 10×g m/s².

The dispenser housing (<b>52</b>) receives a sample on the second frit (<b>74</b>). Application of centrifugal force propels the sample through the second frit, into and through the separation media (<b>70</b>), into and through the first frit (<b>72</b>). The sample is discharged from the dispenser (<b>50</b>) at housing outlet (<b>64</b>).

The sample is discharged in the first chamber (<b>20</b>′) of the vessel body (<b>12</b>′), through conduit means (<b>24</b>′), and into the second chamber (<b>22</b>′). Sample held in second chamber (<b>22</b>′) is substantially isolated from the atmosphere due to the small diameter of the conduit means (<b>24</b>′). Thus, evaporation of the sample is minimised. Evaporation can be further minimized by insertion of a plug element (<b>116</b>) as depicted in <figref idrefs="DRAWINGS">FIG. 2</figref>. Sample Evaporation can be further limited by the liquid from the third chamber (<b>40</b>″) evaporating to increase the content of solvent in the atmosphere in the first chamber (<b>20</b>′) and hence also the second chamber (<b>22</b>′) of the apparatus. Turning now to <figref idrefs="DRAWINGS">FIG. 6</figref>, one or more of the dispenser (<b>50</b>), vessel body (<b>12</b>), and plug element (<b>116</b>) are depicted as a kit (<b>160</b>) for performing separations or for storing samples. The kit comprises suitable packaging, such as box (<b>162</b>). Other suitable packaging comprises wraps, bags, plastic shells and the like. Kit (<b>160</b>) comprises instructions (<b>164</b>) for the use of dispenser (<b>50</b>), vessel body (<b>12</b>) and plug element (<b>116</b>). Of course, any of the vessel bodies (<b>12</b>, <b>12</b>′ and <b>12</b>″) can be substituted in the kit.

Preferably the apparatus (<b>10</b>) is designed such that the second chamber (<b>22</b>) can hold a volume of sample (<b>28</b>) between approximately 100 μl and 1 ml. A typical vessel body (<b>12</b>) may be of length in the range of 1-10 cm, preferably in the range 2-5 cm. The diameter of a typical vessel body (<b>12</b>) may be between 2 mm and 30 mm, preferably in the range 5-15 mm at the first chamber opening (<b>26</b>).

A typical dispenser (<b>50</b>) may be of length 1-10 cm, preferably in the range from 2-5 cm. A dispenser (<b>50</b>) may have a diameter between 5 mm and 50 mm, preferably in the range 10-30 mm at the first end (<b>58</b>). The dispenser (<b>50</b>) may have a diameter in the range 100 μm-2 mm, preferably in the range 200 μm to 1 mm at the second end (<b>60</b>).

EXAMPLE

The dispenser (<b>50</b>) was made by manually packing a dispenser housing (<b>52</b>) using 1.0±0.05 mg of 30 μm Oasis® HLB (Waters Corporation) contained between two polyethylene spherical frits: a 0.035″ spherical frit at the bottom of the bed and a 0.055″ spherical frit at the top of the bed.

Sodium chloride, Angiotensin II, and p-toluamide were obtained from Sigma-Aldrich. Triethylamine (TEA), glacial acetic acid, trifluoroacetic acid (TFA), and HPLC grade acetonitrile were obtained from J. T. Baker. 15-mer oligodeoxythymidine (15-mer oligo T) was obtained from Midland Certified Reagent Company (Midland Texas). 0.1 M triethylammonium acetate (TEAAc) was prepared by adding 2.21 mL of glacial acid and 5.58 mL of triethylamine to 350 mL of H2O. The solution was mixed, adjusted to a volume of 400 mL and pH adjusted to pH 7 using acetic acid. The 0.24% TFA, and 50% acetronitrile were prepared by volume. 50 mM NaCl was prepared by adding 0.0584 grams of NaCl to 1 liter of H2O. 0.1 M TEAAc with 50 mM NaCl was prepared by adding 2.21 mL of glacial acid and 5.58 mL of triethylamine to 350 mL of 50 mM NaCl. The solution was mixed, adjusted to a volume of 400 mL with 50 mM NaCl and pH adjusted to pH 7 using acetic acid. A 60 μL DNA load sample contained 1 μg of 15-mer oligo T and 1 μg of p-toluamide in the 0.1 M TEAAc buffer with 50 mM NaCl. The 60 μL peptide load sample contained 1 μg of Angiotensin II and 1 μg of p-toluamide in the 0.24% TFA. All solutions were pulled through the dispenser <b>50</b> using a centrifuge.

DNA Desalting Method:

1. Condition each dispenser (n=3) with 60 μL of acetonitrile followed by 60 μL of 0.1 M TEAAc buffer

2. Load 60 μL/dispenser of the DNA sample

3. Wash with 60 μL/dispenser of the 0.1 M TEAAc buffer followed by 60 μL/tip of H2O

4. Elute each dispenser with 5 μL of 50% acetonitrile in H2O

Peptide Method:

1. Condition each dispenser (n=4) with 60 μL of acetonitrile followed by 60 μL of 0.24% TFA

2. Load 60 μL/tip of the peptide sample

3. Wash with 20 μL of the 0.24% TFA followed by 20 μL of H2O

4. Elute each tip with 5 μL of 50% acetonitrile in H2O

Vessel body (<b>12</b>) has been loaded with sample (<b>28</b>) which has been stored in the second chamber (<b>22</b>).

A needle is placed through the first chamber (<b>20</b>) and the conduit (<b>24</b>) and into the second chamber (<b>22</b>) in order to pick up sample from the second chamber (<b>22</b>) and pass it on for further analysis.

A person skilled in the art would appreciate that the needle may be a hypodermic or a silica capillary with negative pressure, amongst many others.

A person skilled in the art would appreciate that the further analysis may be performed in a mass spectrometer, A liquid chromatograph, a NMR spectrometer, Ramon Spectrometer, an IR spectrometer, a UV spectrometer, surface plasmon resonance, DNA, antibody or protein microchip analysis amongst others.

Experimental

An experiment to test the relative time taken for a solvent to evaporate was performed comparing a standard vial to a vessel body (<b>12</b>).

<figref idrefs="DRAWINGS">FIG. 7</figref> shows a graph of the relative weights of the two vials against the time for which they have been standing.

Vial <b>1</b> is a vessel body (<b>12</b>) substantially as described previously. Vial <b>2</b> is a standard vial container.

The “vials” were filled with ˜2 mL of methanol (b.p. 65 C) and placed onto analytical balances (enclosed compartment, room temperature 22 C).

The loss of methanol due to evaporation was measured by weighting. The evaporation from vessel body (<b>12</b>) was significantly lower at all times.

Thus, we have described embodiments of the present invention that are preferred with the understanding that the invention is subject to modification and alterations that encompass the invention. Therefore, the present invention should not be limited to the precise details herein but should encompass the subject matter of the following claims and their equivalents.